This invention relates to an improvement in a direct blot electrophoresis apparatus and method for performing direct blot electrophoresis.
Electrophoresis is a separation technique wherein fragments of materials (e.g., DNA) are caused to migrate across a gel in response to an electrical current. The rate of migration is proportional to the molecular weight of the fragment, thus resulting in a separation. In direct blot electrophoresis, such as is taught in U.S. Pat. Nos. 4,631,112 and 4,631,120, the fragments are transferred from the edge of the gel to a moving belt.
U.S. Pat. No. 5,234,559 teaches an improvement in direct blot electrophoresis wherein a membrane, stabilized by a frame, is moved substantially orthogonal relative to the plane of the separation gel. The frame moves at a controlled velocity away from a line of contact with the edge of the gel, which results in a controlled tension in the membrane as a function of the loading on the line of contact between the membrane and the gel.
It is known in the art that the blot patterns produced in direct blot electrophoresis apparatus are sometimes defective; that is, are blurred, smeared, or distorted, which limits the usefulness of that data. The present invention is based on the discovery that such defects in the blot patterns are caused by the evolution of dissolved gas bubbles at the gel/membrane interface.